This invention relates to scraper-chain conveyors as used in mining, and in particular to connection means for connecting the channel sections of such a conveyor.
A variety of devices for connecting the individual channel section of scraper-chain conveyors are known. Such devices normally resist tensile forces which tend to draw the ends of the channel sections apart, and allow some angular mobility between the channel section ends. The connection devices are often subjected to very high forces during operation, not only the tensile forces which they are designed to resist but also buckling forces tending to displace the conveyor ends laterally and/or vertically. Primarily, the lateral forces occur when the conveyor is shifting up to follow the mineral winning progress. This is usually accomplished by means of rams which shift individual lengths of the conveyor in the so-called "snaking" movement. The vertical forces usually occur when a mining machine supported on the conveyor is moved, for example, along the mineral face. Where the floor of the mine working is uneven, these lateral and vertical forces can increase substantially.
One known form of device for connecting the individual channel sections of a scraper-chain conveyor is constituted by a coupling member in the form of a shank provided at each end with a frustoconical centering head (see Nos. DT-PS 2,355,325 and DT-PS 2,400,486). The coupling member is introduced into aligned apertures in coupling elements which are welded onto the channel section ends and the coupling member is secured thereto by means of detachable retaining elements such as C-shaped spring clips. Unfortunately, the coupling member has to be introduced into the aperture in the coupling elements from the front side of the channel sections. Although, this form of device can cope with high working loads whilst occupying a relatively small amount of space, it has the added disadvantage that the retaining elements are loaded by the forces transmitted through the device during mining operations, and this loading can cause them to be detached accidentally, which in turn can lead to the coupling member itself dropping laterally from the coupling elements.
Another known way of connecting the individual channel sections of a scraper-chain conveyor is to provide interlocking coupling elements on the adjacent ends of each pair or adjacent channel sections. One coupling element is provided with a projection which mates, with an all-round clearance, with a recess in the other coupling element. This permits the required angular mobility between adjacent channel sections. Each pair of interlocked coupling elements is connected together by means of screw bolts so that the tensile forces can be transmitted between the channel section ends. This results in a fairly slow and complicated assembly and disassembly process.
It is also known, from No. DT-OS 1,937,018, to join the interlocking coupling elements together by means of a coupling member of the type having an enlarged head at each end of a threadless shank, in which case laterally open recesses are provided in the coupling elements for receiving the coupling member. Here again, however, special retaining elements are necessary to complete the connection, and these can be dislodged during operation.
It is the aim of the invention to provide a connection means for interconnecting the channel sections of a scraper-chain conveyor, the connection means being capable of simple and rapid assembly and disassembly but being such that unintentional disassembly during mining operations is prevented.